A glass tube of 1 ~m length is filled with water. The water can be drained out slowly from the bottom of the tube. If vibrating tuning fork of frequency 500 ~Hz is brought at the upper end of the tube then total number of resonances obtained are [Velocity of sound in air is 320 ~ms ⁻¹ ]

Step-by-step solution

aligned & f =500 ~Hz , v =320 ~m / s & = v f = 320 500 =0.64 ~m =64 ~cm aligned Resonances will be obtained at air columns of lengths aligned & 4 , 3 4 , 5 4 , 7 4 , & 4 = 64 4 =16 ~cm aligned Resonance can be obtained at 16 ~cm , 48 ~cm , 80 ~cm , 112 ~cm , Since the length of the tube is 100 ~cm , only first three resonances can be obtained.